Reciprocating electro-magnetic pump



Aug. 30, 1955 L. c. PARKER 2,716,381

RECIPROCATING ELECTRO-MAGNETIC PUMP Filed July 16, 1952 l I36 45* 55 AORNEY "economical in construction. I 'It is another object to providesuch a RECIPROCATING ELECTRO-MAGNETIC PUMP Leland C. Parker, Elmira, N.Y., assignor to Bendix Aviation Corporation, a corporation of Delaware:Application July 16, 1952, Serial No. 299,111

2 Claims. (Cl. 10325) The present invention relates to a reciprocatingelec 'tromagnetic pump and more'particularly to controlling andregulating means for such pumps.

The present application is in the nature of an improvement on theapplicants prior application, Serial Number 236,935, filed July 16,1951, nowiatent No. 2,631,250.

In that application the contacts which control the operation of the pumparenormally open and are closed mag- 7 novel reciprocatoryelectromagnetic pump which is eflicient and reliable in operation whilebeing simpleand device in which the control of the actuation of thepiston is independent of the movement of the piston.

It is another object to provide such a device incorporating means formaintaining a substantially constant output pressure irrespective of thevolume of delivery, up to the maximum capacity of the pump.

Further objects and advantages will be apparent from the followingdescription taken in connection with the accompanying drawing in which:

Fig. 1 is a vertical substantially mid-sectional view of a preferredembodiment of the invention, the electrical system being showndiagrammatically; and

Fig. 2 is a detail of a modified form of contact controlling mechanism.

In Fig. 1 of the drawing there is illustrated an electromagnetic pumpcomprising a cylinder 1 of non-magnetic material in which a magneticpiston 2 is slidably mounted. A spring 3 normally maintains the piston 2in its upper position as illustrated, and a solenoid 4 is arranged, whenenergized, to draw the piston downward against the force of the spring3.

Circular pole pieces 5 and 6 for the solenoid 4 serve as mounting meansfor the solenoid and cylinder 1, and position these members coaxially ina cylindrical casing 7 which is also of magnetic material and thereforeforms a flux path between said pole pieces.

Casing 7 provides an inlet chamber 8 which receives liquid to be pumpedthrough the inlet nipple 9. The liquid passes through a filter lll,inlet check valve 12, and check valve 13 in the lower end of the piston2, whereby reciprocation of the piston discharges the liquid into theoutlet chamber 14 of the casing 7 which is provided with an outletnipple 15.

The upper end of casing 7 is provided with an outturned flange 16 onwhich a cap 19 is secured in any suitable manner as by crimping over alip 17 of the cap, a gasket 18 being interposed to ensure againstleakage. A backing plate member 32 is soldered in the cap 19, and acircular flexible diaphragm 20 is soldered at its periphery to thebacking plate, thereby effectively sealing the cap United States PatentO27 to complete the solenoid circuit.

2,716,381 Patented Aug. 30, 1955 19; and, when the cap is mounted on thecasing '7, providing a flexible closure for the outlet chamber 14.

Means for periodically energizing the solenoid4to cause reciprocation ofthe piston 2 is provided comprising a battery 21 which is grounded at 22and connected by a lead 23 through a switch 24 to a contact mechanism inthe cap'19 indicated generally by numeral 25." A lead 26 connects thecontact mechanism to'one end of the solenoid 4, the opposite end thereofbeing grounded at The contact mechanism 25 comprises a base or framemember 28 of'any suitable insulating material which is mounted by meansof posts 29 and 31 on the plate member 32. A flexible metallic reed 33is anchored at one end to the frame 28 as by'means of a rivet 34' andwasher 35, and is thereby electrically connected to'the battery lead 23.Reed 33 has on its free end an armature 36 which is normally spaced ashort distance above a pole piece 37 of an electromagnet 38. Oneterminal of the electromagnet is connected by a lead 39 to the batterylead 23, andthe other end is connected by a lead 41 to the lead 26'whichgoes to the solenoid 4.

Reed 33 carries a contact 42 adjacent the armature 36 which contact isnormally spaced a short distance from a cooperating contact 43 mountedon the end of a metallic blade 44' which is' pivotallymounted on ametallic 'bracket45flxed to the frame member 28 by means of a rivet 46.A bowed spring member 47 bears at its ends against the bracket 45 andthe contact carrying end of the blade 44 and serves to urge the bladeagainst its upper stop 48 on the frame 28, or against the lower stopbracket member 49 attached to the frame by a rivet 51, as the blade ismoved through dead-center position'by an operating lever 52 pivoted onthe bracket 45 at 53 and to the blade 44 at 54.

Means for moving the contact 43 into and out of the path of movement ofthe vibrator contact 42 is provided in the form of a plunger 55 slidablymounted in the plate 32, hearing at its lower end at 56 on the flexiblediaphragm 2d, and at its other end engaging the free end of the lever52.

Contact 43 is connected through the blade 44 and bracket 45 to thesolenoid lead 26 so that when the contacts 42 and 43 are in engagement,the solenoid 4 is connected directly to the battery 21, whereas whensaid contacts are open, the electromagnet 38 is inserted in the solenoidcircuit. The resistance of electromagnet 38 is such that when it isplaced in series with the solenoid 4, it prevents effective energizationof the solenoid.

In operation, starting with the parts in the positions illustrated,closure of the manual switch 24 completes the circuit from the battery21 through electromagnet 38 and solenoid 4, whereby the electromagnet isenergized, but the solenoid is not sufliciently energized to actuate thepiston 2. Energization of the electromagnet 38 attracts the armature 36downward toward the pole piece 37, bringing contact 42 into engagementwith contact 43. This short-circuits the electromagnet 38 and connectsthe solenoid 4 directly to the battery 21 whereby the solenoid is causedto draw the piston 2 downward, compressing the spring 3. Thedeenergization of the electromagnet 38 caused by closure of the contacts42, 43 across which said electromagnet is bridged, releases the armature36 allowing the contacts 42, 43 to open, whereby the solenoid 4 is soweakened as to permit the spring 3 to return the piston 2 to its normalposition. Repetition of this cycle of operation causes the piston to bereciprocated, and thereby transfer the liquid to be pumped from theinlet chamber 8 to the outlet chamber 14. When the fluid pressure in theoutput chamber has been thus built up to the desired point, the flexiblediaphragm 20 moves upwardly, which motion is transmitted through theplunger 55 to the lever 52, causing the blade 44 to be moved downwardlybeyond its dead-center position, whereupon the spring 47 becomesoperative to snap the contact 43 out of the range of movement of contact42, and against the back stop 49. The pump is then maintainedinoperative until liquid has been withdrawn through the output nipple l5sufiiciently to reduce the pressure in the outlet chamber to a pointwhere the diaphragm 2 3 releases the lever 52 and thus permits the blade4 to rise and cause the spring 47 to snap the contact 43 back to itsnormal position.

It has been found desirable to fill the cup 19 with an inert gas under aslight amount of pressure in order to prolong the life of the contacts.This arrangement forms a convenient way of regulating the outputpressure of the pump by varying the pressure of the gas on the upperside of the diaphragm 20.

In some instances it may be desired to retard the movement of thecontact 42 in order to increase the stroke of the piston 2. Onearrangement for securing this result is illustrated in Fig. 2 of thedrawing in which the contact 42, is mounted on a blade member 6% whichis pivoted at an intermediate point 61 to the frame member 23 andcarries a weight member 62 for counterbalancing the armature 36. Anadjustable stop 63 is preferably provided f r limiting the downwardtravel of the contact 42, and a spring M is employed for biasing blade61 toward its normal position.

The operation of this embodiment of the invention is the same as thefirst described embodiment, with the eX- ception that the tiltingmovement of the blade 6% is more deliberate than the vibration of thereed 33 so that the pump piston is operated more slowly.

Although certain structure has been shown and described in detail, itwill be understood that other embodiments are possible and changes maybe made in the precise form and arrangement of the parts withoutdeparting from the spirit of the invention.

I claim:

1. in a reciprocating electromagnetic pump a casing having an inletchamber and an outlet chamber, a cylinder connecting said chambers, ahollow magnetic piston slidable in the cylinder, a spring urging thepiston toward the outlet chamber, a solenoid operative to retract thepiston; and means for energizing the solenoid including a normal lystationary contact, a spring-mounted contact normally spaced therefrom,electromagnetic means for moving the spring-mounted contact intoengagement with the normally stationary contact, and a source ofelectrical energy connected through said contacts to the pump solenoid,the contact-actuating electromagnet being bridged across said contacts;including further a cap for said casing forming a housing for thecontact assembly, a fiexible diaphragm which constitutes a partitionbetween the outlet chamber of the casing and said cap, and meansresponsive to flexure of said diaphragm by pressure in the outletchamber for moving the normally stationary contact out of the path ofthe spring-mounted contact.

2. An electromagnetic pump as set forth in claim 1 in which the cap isfilled with gas under a predetermined pressure which opposes the ileumof the diaphragm in response to the output pressure of the pump.

References Cited in the file of this patent UNITED STATES PATENTS1837506 Tice Dec. 22, 1931 1,838,443 Persons Dec. 29, 1931 1,908,092Whitted May 9, 1933 2,229,986 Page Jan. 28, 1941 2,488,384 Dickey Nov.15, 1949 2,578,902 Smith Dec. 18, 1951

